A light emitting diode (LED) device converts an electrical signal into infrared rays or light using a compound semiconductor property, does not use harmful substance such as mercury unlike a fluorescent light to hardly cause environmental contamination, and has a long life span as compared to a conventional light source. In addition, the LED device has low power consumption, excellent visibility due to a high color temperature and low glare effect as compared to the conventional light source and, recently, is widely used as a light source of a vehicle headlamp.
However, a basic environmental temperature of a vehicle headlamp is close to 80° C. due to engine heat. Since the vehicle headlamp is sealed and has low heat radiation property, internal temperature increase has an influence on the life span of the LED. Accordingly, a high-performance heat radiation system capable of efficiently radiating heat generated in an LED is required and thus a fan for heat radiation of the LED is employed.
Conventionally, a heat radiation structure for a vehicle headlamp includes an LED module formed inside a headlamp housing, a heat sink formed on the bottom of the LED module, and a cooling fan provided under the heat sink.
That is, the conventional heat radiation structure for vehicle headlamps radiates heat generated in the LED module through the heat sink formed on the bottom of the LED module and cools the heat sink through the cooling fan, thereby increasing heat radiation efficiency.
However, when a separate cooling fan is mounted in the conventional heat radiation structure for vehicle headlamps, cost and the weight of a vehicle increase and space utilization decreases. In addition, when the cooling fan is used for a long time, the cooling fan overheats and hot wind is generated, thereby decreasing cooling effect.
In addition, the life span of the LED and the life span of the cooling fan may decrease and an electric motor may be applied to the LED headlamp with low power.